Jennifer Boehme grew up exploring the beaches around her home in St. Petersburg, Florida, looking for whatever she could find. Rocks, sand dollars, coquina mollusks – everything the ocean has left behind.
Now, 40 years later, Boehme wants to launch a new treasure hunt. As executive director of the Great Lakes Observing System, she is leading a campaign to map every meter of the lake bottom. According to the marine scientist, this effort will identify hundreds of underwater wrecks, illuminate topographical features and locate infrastructure. The map, she says, will also help ships avoid submerged hazards, identify fisheries and illuminate patterns of erosion, storm surge and flooding. climate change intensifies.
“One of the things that motivates me is the idea of the discovery aspect,” Boehme said. “There’s a lot we don’t know about lakes. We know more about the surface of the moon.”
Only a fraction of the bottom of the Great Lakes has been mapped, and these low-resolution maps were made decades ago, according to the Great Lakes Observing System, a nonprofit organization that manages data for a network of lake observers and makes them easily accessible. . The National Oceanic and Atmospheric Administration certified the Great Lakes Observing System in 2016 as meeting federal standards for data collection and management, allowing the federal government to use its data without additional review.
The organization has been working since 2018 to create high-resolution maps of the five Great Lakes bottoms, but it is a daunting task. The lakes cover 94,250 square miles, an area larger than the state of Kansas. Depths vary from 210 feet in Lake Erie to over 1,300 feet in parts of Lake Superior.
Tamara Thomsen / AP
The idea has been gaining traction since technology has improved and scientists have completed high-resolution mapping of the coasts of Florida and the Gulf of Mexico over the past three years. Two Michigan congressional representatives – Republican Lisa McClain and Democrat Debbie Dingell – introduced a bill this year that would allocate $200 million to map the bottom of the Great Lakes by 2030.
“I believe it is time to take charge of the exploration and discovery of the Great Lakes,” McClain said at a House subcommittee hearing in March.
The last attempt at mapping the lakes was in the 1970s. The maps were largely created using single-beam sonar technology similar to currently commercially available fishfinders and fish finders. The system produced maps covering only about 15 percent of the mostly coastal lake bottoms, said Tim Kearns, a spokesman for the Great Lakes Observing System. With only one survey every 500 meters (547 yards), the maps were extremely low resolution and could have missed sinkholes, canyons, sand dunes, shipwrecks and infrastructure such as pipelines, cables and intake lines, Kearns said.
Fast forward almost half a century. Scientists and engineers now have a range of new mapping tools at their disposal.
One of them is a multibeam sonar. Rather than sending out a single sound wave, these systems potentially bounce hundreds of them off the bottom. The technology is so sensitive that it can detect air bubbles in water, according to NOAA.
The only drawback is that the systems must be mounted on submersibles or towed under ships to obtain high-resolution images in deep water.
Another tool is laser imaging, where scientists measure the time it takes for a laser beam fired from an aircraft to reach an object and bounce back, providing three-dimensional imaging of the bottom’s topography.
A high-resolution map of the lake bed would provide multiple benefits, said Steven Murawski, a biological oceanographer at the University of South Florida who has done extensive seafloor mapping of the Florida coast and Gulf of Mexico.
The Great Lakes map would provide more complete images of bottom features that have changed over the past 50 years due to erosion and shifting sands, providing mariners with new depth data that would improve navigation safety. navigation, Murawski said. A map would also help predict how bottom features affect storm surges and flooding as climate change continues, which he said would be invaluable information for insurance companies and municipal planners.
Improved background maps would also provide precise locations of infrastructure such as pipelines that have changed over time, crucial information for dredging and construction projects, Murawski said. He pointed out that he has mapped some 50,000 miles of pipelines in the western Gulf of Mexico and that “they are never where they are supposed to be.”
Additionally, high-resolution maps would identify underwater outcrops and ledges where fish tend to congregate, allowing scientists to obtain better estimates of the fish population, the oceanographer added.
“Deadline for our generation”
Comprehensive mapping of the lakes for the first time could also reveal the locations of hundreds of shipwrecks – some estimates put the number of shipwrecks in the Great Lakes at around 6,000 – and relics of ancient coastal civilizations, Boehme said .
Several wrecks have already been spotted in the lakes in recent months. In July, the wreck of the schooner Margaret A. Muir was found off the coast of Wisconsin, more than 130 years after it sank into the bottom of Lake Michigan with the captain’s beloved dog on board.
In April, the Great Lakes Shipwreck Historical Society announced the discovery of the banks of Adellawhich sank to the bottom of Lake Superior without survivors on May 1, 1909.
Michigan Wreck Research Association
This discovery was announced just weeks after the sinking of the Milwaukee steamboat was found more than 350 meters below the surface of Lake Michigan.
A few months earlier, a man and his daughter on a fishing trip found the remains of a ship which sank in Lake Michigan in 1871.
Time is running out to locate the wrecks because many are encrusted with invasive species, according to the Great Lakes Shipwreck Historical Society.
“The proliferation of invasive species has now created a deadline for our generation and future generations; many shipwrecks have already had so many of their features corrupted by mussels that they have become impossible to study,” the organization says.
Even as momentum for mapping builds, Congress has not acted on the funding bill since the March hearing before the House Natural Resources Subcommittee on the water, wildlife and fishing. The subcommittee chairman, Rep. Cliff Bentz of Oregon, suggested during the hearing that supporters were doing a better job articulating the value of a new map.
“I know some high-ranking members have suggested that finding the Edmund Fitzgerald would be a valuable thing, but there has to be more to it than that,” Bentz said, referring to the freighter that sank in Lake Superior in 1975. The wreckage was actually found a few days after the ship was found. fell.
Bentz spokeswoman Alexia Stenpzas did not respond to an email from The Associated Press seeking comment on the bill’s prospects.
Boehme said she doubted the bill would gain traction in an election year, but the Great Lakes Observing System is still working toward its 2030 mapping goal. The group holds an annual conference in Traverse City, Michigan, to discuss progress and test the mapping technology and contacted all boaters willing to take mapping equipment, giving them a glimpse of small pieces of lake bottom.
“This research is for the public good,” Boehme said. “The key is persistence, coming back again and again and making your case (to Congress). … We have to understand the system so we can keep it.”
